The current standard of care for patients with significant aortic valve disease is still surgical aortic valve replacement. As the treatment of many cardiovascular diseases has become minimally invasive and catheter-based, endovascular techniques and equipment has led to the development of percutaneous aortic valve (PAV) replacement as a potential clinical reality. PAV replacement is currently an investigational procedure.
The notion of PAV replacement was first introduced in 1992 by Andersen et al in a swine model [Andersen H R et al., Eur Heart J 1992; 13:704-7081]. The first human implantation of a percutaneous valved-stent was performed in the pulmonic position as reported by Bonhoeffer et al., in 2000 [Bonhoeffer P, et al., Lancet 2000; 356:1403-1405]. The first human implantation of a PAV was described in 2002 using a valved-stent design by Cribier et al via the antegrade/inter-atrial septal puncture approach [Cribier A, et al., Circulation 2002; 106 (24):3006-3008]. Other techniques such as retrograde and transapical approaches of delivery and deployment of the PAV were later introduced [Webb J G, et al., Circulation 2006; 113:842-850; Lichtenstein S V, et al., Circulation 2006; 114 (6):591-596].
In the PAV replacement procedure, most of the cardiac complications occur at the required precise placement of the PAV during implantation. Due to the aortic valve's close proximity to the coronary ostia on one side, and the mitral valve on the other, misalignment of the PAV can cause serious compromise of coronary or mitral valve function [Boudjemline Y, et al., Circulation 2002; 105 (6):775; Ferrari M, et al., Heart 2004; 90 (11):1326-1331]. The significant hemodynamic forces encountered at the left ventricular outflow tract to the ascending aorta, together with the anatomic structures comprising the native valve, add to the difficulty of precise placement of the PAV and the risk of device embolization.
Objects of the present invention include providing a PAV delivery and deployment system that demonstrates structural integrity and that includes specific features to optimize precise PAV placement and deployment while maintaining patient stability. Precise PAV placement and deployment can be facilitated by removing anatomic structures that can hinder or interfere with precise PAV placement, and by minimizing the hemodynamic forces encountered by the surgeon during the PAV replacement procedure. Maintaining patient stability during the replacement procedure can be facilitated by providing a substitute valve that promotes coronary perfusion while moderating stresses (aortic insufficiency and aortic stenosis) experienced by cardiac muscle prior to the PAV becoming operational.